Global glaciation 720-630 million years ago could not have been as great as scientists thought. Reported by TASS.
The first glaciation period is believed to have begun on Earth 720-630 million years ago. Scientists call this period the cryogen, it is characterized by equatorial regions minus the ice that covers the entire surface area of the earth. This period lasted several tens of millions of years with episodic warming. Many questions remain, including what exactly led to this period, how life managed to survive under the ice, and what subsequently caused global warming.
Xiao Shuhai of Virginia Tech in Blacksburg and colleagues studied Neoproterozoic rocks from the southern Chinese province of Hubei. The Nanto geological formation located there formed about 650-635 million years ago and falls on the first global glaciation.
At that time, southern China was in temperate latitudes, near the 30th parallel of northern latitude. Therefore, in the past, paleontologists and geologists believed that this part of the continent and adjacent areas of the seas was covered with a thick crust of “eternal” ice, under which multicellular life could hardly exist.
Excavations in the Shennongjia forest in Hubei province have shown these ideas to be faulty. In the local Proterozoic rocks, the researchers were able to find numerous traces of algae that supposedly grew at the bottom of shallow seas, as well as organic sediments and chemical traces of the presence of significant oxygen in the upper layers of seawater. covered this part of China in the distant past.
All this suggests that, as scientists note, at the end of the cryogenic period, this part of Earth’s primary ocean was ice-free. From this it follows that the ice only reaches relatively high latitudes or has large polynyas in it. Both this and another fact can significantly increase the chances of preserving life on the planet.
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